Fleury went on paternity leave in early December and is expected back "in a few months," Red Hat said in a statement. According to Fleury's automated e-mail response, it's his fourth child, and Fleury will return to work on March 15.

But an e-mail Fleury sent to a select group of JBoss colleagues takes a very different tone and raises questions about his prospects at Red Hat.

"I am going to take some time off to take care of family and myself. I am increasingly experiencing diminishing returns on my emotional and professional investments at Red Hat," Fleury said in the December note seen by CNET News.com. "Working with all of you at JBoss has been a pleasure and probably the apex of my short career."